The present invention relates generally to document handling systems, and more particularly to a document handling system including a document feeder station operative to feed documents in successive one-at-a-time fashion to a transport conveyor, and having a novel system speed control enabling adjustment of both feeder and transport speeds with a single control without having to adjust the gap between successive documents.
It is a conventional practice in various document handling systems, such as mailing machines, to employ a document feeder station operative to feed documents in sequential one-at-a-time fashion from a generally vertical stack to a transport station employing at least one conveyor belt operative to convey the documents in spaced relation along a predetermined path. As the documents traverse the transport path, they generally pass one or more operating stations which perform various functions on the documents, such as applying alpha-numeric indicia to each document. Mailing systems of this general type are commercially available from Videojet Systems International, Inc., Wood Dale, Ill.
In document handling systems of the aforedescribed type, the document feeder and transport stations each typically employ a separate controller having a drive motor responsive to control signals to vary the motor speed, and thus the document feed rate (documents per hour) and transport speed (feet per minute). By selectively varying the feeder and transport drive motor speeds, variable spacing may be obtained to accommodate different size documents. Present mailing machines that have variable spacing typically use independent electronic speed controls for the feeder and transport drive motors. The speed of the feeder is set independently of the speed of the transport. If the speed of the transport is changed, the gap between documents or other pieces of media either becomes larger or smaller. This may cause a crash or jam to occur between successive documents or media pieces, or result in a loss of production because of excessive gaps. The feeder and transport drives of present mailing machines must be set by adjusting both controls and then fine tuning. The desirable approach is to set both feeder and transport speeds proportionally with a single speed control, and set the gap with another control. Thus, an inexpensive control for proportionally adjusting feeder and transport speeds manually with a single control, and adjusting the gap between successive documents with another control would provide a significant advantage over prior known mailing machines.